Mecanismos de Compartilhamento de Custos em Saúde – Parte I: evidências dos experimentos RAND e Oregon

This paper, the first in a series on health care cost-sharing mechanisms, provides a detailed review of two landmark experiments in health insurance: the RAND Health Insurance Experiment and the Oregon Health Insurance Experiment. It revisits their experimental designs, identification strategies, outcome measures, main findings, and limitations, with particular attention to the mechanisms through which insurance coverage and patient cost sharing affect health care utilization, expenditures, and health outcomes. The two experiments provide complementary evidence. The Oregon experiment shows that obtaining health insurance coverage increases health care utilization and improves financial protection, whereas the RAND experiment demonstrates that cost sharing reduces utilization, primarily by affecting the decision to initiate care. The RAND findings also indicate that reductions in utilization are not necessarily concentrated on low-value care, since clinically necessary services are also affected, and that health effects are heterogeneous, with greater benefits from full coverage among low-income individuals in poorer initial health. Taken together, the evidence shows that the price faced by patients significantly affects the demand for health care, while also highlighting the limitations of cost sharing as a stand-alone instrument for improving the efficiency of health care utilization.